Getter structure for electric discharge tubes



Jan. 3, 1950 E. G. DORGELO 2,493,659

GETTER STRUCTURE FOR ELECTRICDISCHARGE '.I'UBES Filed Feb. 14, 1947 /NVENTOR E. G. DORGELO AGENT iatentecl `lan. 3, 195() nis'oHARGE TUBES.

Eduard Gerardus Dorgelo Eindhoven;v lands, assignor'toilHartford National Bank and Trust. Company, Hartford, Camry, as trusteevv ApplicationFebruary'lL 1947, Serial No. 728,573.

In ther'Nethelilands Marck 1i; 194411" sections, Public Law 69o, August s, 1946 Patent expii'cs Manch..1 1.1964

Thi'sjinvention' relates' to' an electric' discharge'V tube' comprising'an anode cooled artificially; a gaseabsorbing' material such,. fonexample, as`Y zirconium, thorium titanium. or tantalum' beingn provided'inside'thetube:

It' i's known to' utilize' these materials as" a`l getter'in electric' discharge tubes, more' p 'articu-'- larly'in transmittin'g; tubes, and'r to' apply' such` materials" at severall points.4 In this case ther problem is involved that the materials rn-ust have acomparatively high temperature; also during the' operation o'f tlietube'; inlorder' permanently' to obtain a'` satisfactory gaseabsorbing action: It has previously been suggestedifor'ith'is purpose'A either tov apply zirconiumto grids ora-nodes, or toarrangezircon-ium'so as to' bel contact with the cathode; The application of|`v zirconiunrv tot` gridsmay lead?2 tothe secondary grid-emissionfbeing strongly suppressedfan'd this is 'undesirable in definitefcas'esy since" more particularly in the caseof trainsmittingi tubesa certainsecondarygridf-*emissionis necessary for the suppression'cf 'f the grid' current. The arrangementof 'zirconium or a similar metal having a satisfactory gases absorbing capacity inn contact with ytl'i'e cathode may in definite2 cases@ involve the drawbackfthatthemetal` does`Iv noti' attain a*- temperature sutil cientlyfhig'h for'the absorption of all the-residual-A gases and, in addition, cannot be utilized in tubesofthe'modern'- type.

As'- a-z rule, the application of zirconium tothe anode yields 'satisfactory results.

arti-ii'ci'ally.`,'v the diiicu-lty isinvoivedthat, as before, the temperature required for ak satisfactory absorption ofk gaslvis'not'attained'; In addition, itdsnot atsimple. matter toapply they zirconium thoroughly to such an anodewhich, ass a nula'fv consists of copper, since for the fastening by sinterng cox'nparati'velyx highV temperatures are requiredifwith the result that-:the copper anodeT tificially, a body of refractory material, covered'- with a gas-absorbing metal, such as zirconium, thorium, tantalum, titanium or a similarmaterial is fastened to the anode so as to be in incomplete heat-conductive contact with it.

In desintecase's, however; morerparticularly wnenthe" gas-Jy' absorbing material is applied to an anode cooled? body' and? at the' samei timefor the' ari-ode, cooiedartincauy; so' asto k'be in incorn-I plete neat-#conductive cont satisfactory somti'on "for" rast ning4 or" t Y i l v `Heating; and; a-isoror' tire' dissipation' of neat; while trie' gas:- absorbing, meta soiuerin'g to' thistody teforenandt;

-vmatenar-fori thev carrier' tout use" is. sfere errati-y maus offr'rrowbuenum.tunestenora simi' nar refractoryrmetaifjv'rims-.body', before Being* secured tothe' annue; is'cov'ered" in" a known mannerv Aoni'uin Vora similar'gasabsorbi ing metal, whichis slnt'ered :on'it at highteiiil' perature. l y K v lEtr will be' cliearfrorn the'rregoingwhat is' to be understood Vloy the'u terni"l incoireplete''y heat# conductive-contact? This" refers' to" a' contact suchthat theiljody' acquires sunicien'tly tigri.' temperature whilst" avoiding,n ,on2 the 'other hand; excessives heating'- by-f means oriappropr'iate` conv tact"y 'W'ith the c'llcd'anode which, as "a' rule," is'a'lsir' anI electricfcontac 'Itdependson' circumsta'n'c'esUT when these crniiiit-iionsfarer fuliilled As a' rule'," however; an='incomplete*heatconductive' Contact exists-"when the@ anodejandfthe carrier body' for" the-1 gas-'absorbing'fmateri'ar are in Contactl witli'i eaxzlr-other butido'- 'not 'Iake" Contact" through large portion` of tlieiirsurfaces;` thecontactpoints being"formedibytmeansor operationsa's soi'derin Welding land it f -ili 'Il'iefrni and'thei fasten-'r'4 ing'- of'y messia* body-"fri-eolu'e'ntl'y'f depend on the" snapshot? theg anodef Vi'rv avl particular formil or"j construction c afltulefaccornihg- "toV the irivenaf' tion, thejc'ar' iiirthi-gais-labsorbihgi metal-isi.: constitutediby'- ai cylinder whi'cli'f sur'rciin'ci's14 the V' i'nside""the I'atterl` 'fh fasteningfmaybefreircted for-'example byistar ing-@front a split y-liiiorvand bitA depressing nie lattoriatisome points and "sutsectiontryionamin@- iiarouadi or i'iasiuetrie't anode; so that contact between the two objects exists only at the points depressed. The zirconized body may alternatively have the shape of a helix or a Vspiral clamped around or inside the anode, itl being possible for the anode to be provided with grooves in order to make the helix contact at a few points only. Furthermore, use may be made of rods covered with gas-absorbing material,

3 which are laid into grooves of the anode and are clamped on the latter, for example, by means of some turns of zirconium wire.AEA Y. Y. In order thattthe.,invention may (be"clearlyk understood and readily carried into eiect, it will now be described more fully with reference to the accompanying drawing.

Fig. 1 shows a tube according Fig. 2 shows a detail of the tube of Fig. 1'.

to the invention. i

Fig. 3 shows a detail of anzanode comprising grooves. Y i Fig. Y4 is a helical body covered with gasabsorbing material, and

Fig. 'shows a particular form of'constructi'on of a tube according to the invention, i. e. `of a `soca11ed transit-time tube. e'

Figure 6 shows a rod shaped body covered'with f in the grooves of the anode. In Fig., l, reference 1 indicates thecylindrical anode* cooledartificially,which may be' cooled by means of a liquid supplied throughthe tubeV 21g The anode I is Ysealed to the wal1'3jwhich may be of metal or glass of the tube and constitutes itself also a portion jof the wan. The anode is suie rounded bya grid 4 and acathode 5. A split cylinder 6 of molybdenum,'superiicially covered with zirconium, isclampedaround the anode I. The

' cylinder is depressed at some points 1, as is shown clearly in Fig. 2, s o that heat-conductivev contactv between the A,cylinder 6 and the lanode I VVexists only at these points.

Instead of withV depressed*portionsl of the cyl#A inder 6, satisfactory results may also be obtained by clampinga smooth s'plitvcylinder I0 (Fig. 3)V

around an anode 8 `comprising grooves 9. i,

Jrig. 4 shows a helical zircoms'ed body which may be fastened in an ,anode which, if desired, Vmay comprise groove'sfof, opposite Vdirection of Y winding. Fig. 5 ,shows a portion of aso-called transit` time tube in .which the electrons 4ir'ithe form of .a

ofthe distance from cathode to anode, the velos-.- ity of the electronsis. modified, the construction being such that the rapid electrons are enabled to overtake the slowones. Tubes of thisY kindoperate/at very high frequencies andhigh voltages, resulting in a strong heating'.V of kthe anode I5.. at

4that point Vat which the electronvbeam impinges tube of this kind, as is shown in Fig. 5. Inside the anode VI5 is arranged aY split .molybdenum cylinder I3 coveredwithagas-absorbingmaterial. inthe above-described form of construction,

beam "run to the anodell During'the covering f gas-absorbing material, said body being positionedY Vcoil III and by means of a displacement of this coil the electron paths may be so influenced that theelectronsinside theanode. cylinder are more orless divergent, so that the electrons impinge on the cylinder I3 to a greater or less extent. The temperature and hence the gas-absorbing action of the zirconium can thus be controlled in a simple manner. The divergence is preferably controlled in such a manner that the cylinder I3 is red-hot during the operation of the tube.

Figure 6 shows ai helical rod shaped body Il,

f coated with a gas-absorbing material such as zirconium, and positioned in the grooves of an anode, I8.

Although only a few forms of construction have been described, Vit 'is evident that the invention is I' realizable in many other ways.

What I claim is:

1. An electric discharge tube comprising an artii'lcially cooled anode electrode, a body of-refractory material in poor thermal contact with said anodeelectrode, and a gas-absorbing metal sintered to said refractory body.

2. An electrice discharge tube as claimed claim 1, wherein a refractory body covered with a gas-absorbing metal' is secured to a copper anode, said anode being cooled artificially and being in heatconductive contact with said refractory body at a few points only.

V3. An electric discharge tube as claimed in claim 2, wherein the body covered with the gas-I absorbing metal has the shape of a split cylinder depressed at some points.

4. An electric discharge tube as claimed in claim 1, wherein the anode is provided with grooves, and the refractory body covered with the gas-absorbing metal isin heat-conductive contact with the projecting surface of the anode.

5. An electric dischargev tube comprising an articially cooled anode,A a body of refractory ma-A terial in poor thermal contact with said anode,.r and zirconium metal sinteredto said refractory body.

6. An electric discharge tube rcomprising an ar-` i ticially cooled anode, a body of refractory ma-A terial in poor lthermal contact with said anode,

and titanium metal sintered to said refractory body.

'7. An electric ticially cooled anode, a body of refractoryl material in poor thermal contact with said anode, z

and tantalum metal sintered to said refractory body.

cylindermay comprisedepressed pcints. If dec Y sired, theV anode may in'part,beturned out,jso

that thecylinder isvenclosed and Iis prevented from being displaced'or falling ,out Q'Lthefanodeg,

The wall I2 of the tube is surrounded by a magnet EDUARDGERARDUS DORGELO. y.

YREFERENCES errno Y,

'The following references leof patent:

UNITED STATES PATENTS Number Name DateV 1,700,945.v r Loppacker Feld- 5, 1929'- Y 2,263,164 Dailey I NOV. 18, 1941 T 2,368,060 Wooten Jan.23,1945Y discharge tube comprising an are.

are of recordin the Hansen et a1. 1 oet. 29,1946' 

